Comparison

Units Free vs Unit Converter For Engineers

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Units Free

Easily convert between various units across multiple categories like length, temperature, and weight. Access past conversions through a history list and send calculations via email. This free version offers core functionality with an option to upgrade for full category access.

Highlights
  • Multiple unit categories (length, temp, weight, etc.)
  • Metric and imperial system support
  • Conversion history list
  • Send calculations via email
  • iPad multitasking support
Features
Read full description

Convert between many units from several categories and different unit systems (metric, imperial, ...). Features: - categories: length, temperature, capacity, weight, energy, power, pressure, area - access previous conversions from the history list - categories have different colors (in the history as well) - flip units - send calculations by email - support for the iPhone 6 and 6+ - support for the iPad multitasking (split view..) (Free version: requires upgrade to arbitrarily switch categories)

About

Unit Converter For Engineers

This app provides a comprehensive unit conversion tool specifically designed for engineers, offering specialized units not found in standard converters. It features offline functionality, fast search, and a clean interface, replacing the need for multiple reference materials.

Highlights
  • Specialized engineering units
  • Offline functionality
  • Fast search and instant conversion
  • Fraction input mode
  • Ad-free interface
  • Scientific notation support
Features
Read full description

Built for engineers who work with units most converters don’t have. No ads. No popups. No distractions. If you’ve ever opened PDFs, charts, or old handbooks to convert Rockwell hardness, wire gauge, HVAC airflow, radiation dose, water hardness, or torque units — this app replaces all of that. Units you usually can’t find in converter apps Material Hardness Rockwell (HRC, HRB, HRA), Vickers, Brinell, Knoop, Mohs, Shore Wire Gauge AWG, SWG, MCM, kcmil, diameter, cross-sectional area HVAC & Airflow CFM, ACH, BTU/h, tons of cooling, kW, airflow per area and per person Water Quality & Chemistry ppm, mg/L as CaCO₃, grains per gallon (US/UK), °dH, °fH, dKH, mmol/L, meq/L Radiation & Radioactivity Becquerel, Curie, Gray, rad Mechanical & Structural Torque, stress, density, pressure, moment of inertia (kg·m² ↔ slug·ft²) Built for real work environments • Works 100% offline in labs, plants, and job sites • Fast search and instant conversion • Scientific notation for precision work • Fraction input mode for field and construction use • Clean, engineer-friendly interface — no ads, ever This app replaces reference charts, calculators, handbooks, and repeated Google searches with one reliable tool in your pocket. Pricing 7-Day Free Trial $9.99/year full access $29.99 lifetime access Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://unitconvertx.github.io/docs/privacy.html

Screenshots

Units Free4 screens
Unit Converter For Engineers4 screens

Verdict

The call

The clearest difference is review sentiment: Unit Converter For Engineers at 100% against Units Free's 0%. Unit Converter For Engineers also leads on rating (5.0 vs 1.0) and update cadence (every 9 days vs every 5 months). Units Free's advantage is iOS requirement (5.1.1 vs 16.2). On price, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Units Free sells 1 one-off in-app purchase and Unit Converter For Engineers sells 2 in-app purchases, starting at $9.99 per year. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Unit Converter For Engineers holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 3 respectively. Written reviews point the same way: 0% of Units Free's written reviews are positive against 100% of Unit Converter For Engineers's.

UpkeepUpdate frequency

Units Free ships an update every 5 months, Unit Converter For Engineers every 9 days. The most recent releases landed on November 6, 2026 and October 30, 2026 respectively.

Scorecard5 real differences · 5 level
Units Free versus Unit Converter For Engineers: the parameters behind the verdict, then further details
ParameterUnits FreeUnit Converter For Engineers
PriceFreeFree
Rating1.0 (1 ratings)5.0 (3 ratings) — better
Positive reviews0.0% of reviews100.0% of reviews — better
Number of ratings13 — better
Update frequencyEvery 5 monthsEvery 9 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFreemium
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS5.1.1 — better16.2
Further details — not scored
Size3 MB5 MB
Age rating4+17+
DeveloperPiet JonasAmanuel Abebaw

Customer experience

Units Free

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews15 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Unit Converter For Engineers

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

1 purchases

Units Free

One-time1
  • Units Free Upgrade$0.99
2 purchases

Unit Converter For Engineers

Subscriptions1
  • Annual Subscription7 Days trial$9.991 Year
One-time1
  • Lifetime Access$29.99

Questions

Is Units Free free?
Units Free is free to download, with in-app purchases available.
Is Unit Converter For Engineers free?
Unit Converter For Engineers is free to download, with in-app purchases available.
Which has better reviews, Units Free or Unit Converter For Engineers?
Unit Converter For Engineers is rated higher. Units Free averages 1.0 out of 5 from 1 ratings, while Unit Converter For Engineers averages 5.0 from 3 ratings.
Do Units Free or Unit Converter For Engineers have ads?
Neither Units Free nor Unit Converter For Engineers shows ads.
Which is updated more often, Units Free or Unit Converter For Engineers?
Units Free ships an update every 5 months, and Unit Converter For Engineers every 9 days. Most recently, Units Free was updated on November 6, 2026 and Unit Converter For Engineers on October 30, 2026.

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